San Francisco Transbay development

Designed by Pelli Clarke Pelli, the new Salesforce Transit Center replaced the former Transbay Terminal at a cost of roughly $2 billion USD[14] and has been dubbed the "Grand Central Station of the West" by proponents.[15] The new center is planned to eventually include an extension of Caltrain into the station from the current Caltrain Depot at 4th and King Streets in Mission Bay via tunnels which would also carry the Bay Area segment of the future California High-Speed Rail (CAHSR) and terminate at the station, as mandated by California voters in Proposition 1A, the ballot measure authorizing CAHSR construction. This extension would cost an additional $2-4 billion and is currently unfunded.[16]

Salesforce Transit Center construction site.

The Transit Center currently has three levels plus a 5.4-acre (2.2 ha) public rooftop park. The ground level is the street entrance to the Transit Center. Above that are administrative offices, retail shops, restaurants, and the Amtrak/Greyhound waiting room. The final indoors level services Transbay buses from San Francisco's Muni, the East Bay's AC Transit, and WestCAT, as well as long-distance buses operated by Greyhound and Amtrak Thruway.[17] Future Caltrain and HSR service would utilize two underground levels, the lower of which would house the tracks and platforms, and the upper of which would house a retail concourse and waiting areas.

Adjacent to the Transit Center and at the center of the redevelopment effort is a signature skyscraper at First and Mission Streets. The proposal featured plans from several major architecture firms including Skidmore, Owings & Merrill, Richard Rogers Partnership, and Pelli Clarke Pelli Architects. Eventually the plan from Pelli Clarke Pelli Architects was picked.[18] The original plans from Pelli Clark Pelli Architects called for a 1,200-foot (370 m) tower as the main tower and a massive three-block-long Transbay Center. However, due to considerations about how the tower would cast a shadow over some of the city's parks, the height was eventually reduced to 1,070 feet (330 m).[19][20]

The designs to the supertall tower changed during its planning phase, its final design eventually incorporates slits at each side of its angular top along with an altered terminal station design.[21] However some of the original design cues were later restored and reincorporated due to complaints about the design modifications.[22] The tower and the new terminal is now under construction with groundbreaking on March 27, 2013.[23]

With the adoption of the Transit Center District Plan in 2012, height limits were raised for several parcels in the vicinity of the Transit Center.[24] Among the parcels zoned for taller buildings are 50 First Street, 181 Fremont Street, 350 Mission Street, Golden Gate University's campus at 536 Mission Street, the proposed Palace Hotel Residential Tower, and the Salesforce Tower site.

Following the 1989 Loma Prieta earthquake, the Embarcadero Freeway was torn down, opening up a number of blocks for development. Several other parcels, near Beale and Howard streets, were used for the East Loop Ramp of the Transbay Terminal and are not needed for the new Transit Center.[25] In 2007, the state of California officially agreed to transfer the state-owned parcels to the City and County of San Francisco.[26]

The former freeway parcels are located mostly along the north side of Folsom Street between Essex and Spear and have been zoned for residential use.[27] Other lots, called Parcel F, Parcel M, and Parcel T, have been zoned for office buildings.[28] Parcel T is the site of Salesforce Tower. As of 2013, Transbay Joint Powers Authority has accepted proposals for Blocks 6/7 and Block 9.[29][30] The first parcel developed was Block 11, also known as the Rene Cazenave Apartments, an affordable housing project located at 25 Essex Street.[31]